Interestingly, a strong negative association between IDO2 DNA methylation and age was seen both when comparing SCD, MCI, and dementia patients (model 1: β = −0.11, S.E. = 0.04, p = 0.006, 95% CI = −0.19 to −0.031) and when comparing converters to non-converters (model 1: β = −0.14, S.E. = 0.053, p = 0.009, 95% CI = −0.24 to −0.035). This evidence concerns the gene IDO2 and dementia.